* pkg/pg: Add new service function storage node
Add a new service function to the storage node piece store for deleting
pieces when satellites request them.
* storagenode/piecestore: Add endpoint to delete piece
Add a new endpoint to receive from trusted satellites to delete a piece.
* private/testplanet: Fix storagenode mock
Add to the storagenode mock the new endpoint method.
* proto.lock: Update it with the last protbuff changes
* storagenode/piecestore: Reuse test piece upload
Extract the repeated logic from several tests functions for uploading a
test piece to a test helper function.
* uplink/piecestore: Implement client side method
Implement the client side method of the new piecestore RPC function.
* storagenode/piecestore: Add test DeletePiece endpoint
Implement a test for the DeletePiece new endpoint method.
* Make the exiting node check piece hashes, piece IDs, and piece hash signatures before relaying successful transfer data to the satellite.
* Enable immediate graceful exit failure for "successful" transfers that fail satellite-side validation.
* Move transfer piece logic in storagenode worker to separate function (to make the worker easier to understand)
all of the packages and tests work with both grpc and
drpc. we'll probably need to do some jenkins pipelines
to run the tests with drpc as well.
most of the changes are really due to a bit of cleanup
of the pkg/transport.Client api into an rpc.Dialer in
the spirit of a net.Dialer. now that we don't need
observers, we can pass around stateless configuration
to everything rather than stateful things that issue
observations. it also adds a DialAddressID for the
case where we don't have a pb.Node, but we do have an
address and want to assert some ID. this happened
pretty frequently, and now there's no more weird
contortions creating custom tls options, etc.
a lot of the other changes are being consistent/using
the abstractions in the rpc package to do rpc style
things like finding peer information, or checking
status codes.
Change-Id: Ief62875e21d80a21b3c56a5a37f45887679f9412